my app just works fine if I dont use the live view function.
However, I want to use the live view function.
When I turn it on, the app seems to stop working (cant take pictures, wont show the live view).

That was an issue that was fixed in an update some weeks ago.
Can you please check the version of Wifibooth: go to Settings App -> Wifibooth, version is at the bottom.
If it is less than 4.4.8 then please go to App Store and update.
Did that fix it?

Please write a review for Wifibooth on the Apple App store! Indie developers like me really need people like you to review their apps. Instructions on how to write a review: http://goo.gl/w8NsDI.